One of the most popular FM stations in London in the 1980s was London Weekend Radio. The station also helped launch the careers of Radio 1 DJs Tim Westwood and Pete Tong.
There is more about LWR at: http://wikibin.org/articles/london-weekend-radio.html
There also a longer, better quality recording at: http://radio.eric.tripod.com/lwr.htm
Also here: http://www.thepiratearchive.net/lwr.html